How can I select 2 specific edges all around this gear?
You can use Checker Deselect for this.

Select all the edges around using Select &gt; Edge Rings
Deselect one of the edges (Shift + LMB) to break the loop
Use Select &gt; Checker Deselect (play with the values, and adjust offset if needed)
Add that one edge to selection (again using Shift + LMB)